Optical bistability is the phenomenon whereby a system can exist in one of two stable states for a given incident light intensity. This bistable behavior can be utilized for optical switching, optical digital memory elements, and intensity-limiting behavior, as well as transistor action (the optical counterpart of the electronic transistor). Such devices can be incorporated in all-optical communication systems, data processing systems, and logic operations in an all-optical digital computer.
It has been shown that optical bistability without an optical cavity can occur in a transparent dielectric material which has conducting microparticles randomly and independently distributed throughout it. This is taught by D.S. Chemla and D.A.B.. Miller in an article titled "Mechanism for Enhanced Optical Nonlinearities and Bistability by Combined Dielectricelectronic Confinement in Semiconductor Microcrystallites" published in Optics Letters, Vol 11, No. 8, August 1986, p. 522. This bistability in the material is intrinsic since it does not require the use of an external cavity or other forms of optical feedback.